This application is directed to a machined contoured passage for airfoil trailing edge (TE) cooling and, more particularly, to a machined contoured passage for airfoil TE cooling in which the contoured passage mimics a shape of the airfoil TE.
Recently, it has been observed that a passage that extends through a trailing edge (TE) of a nozzle airfoil may be employed to cool the TE during use of the airfoil in, e.g., a turbine engine. The cooling process involves forcing a coolant, such as water or steam at high pressure, through the passage. Typically, however, nozzle design involves high temperatures that heat the TE and therefore require that the TE have thin walls that may be cooled from an interior of the airfoil. As such, the combination of the thin wall requirement, the high external temperatures and the high internal pressure require the TE cooling passage to be very small and the walls of the TE cooling passage to have certain dimensions and thicknesses.
While casting technology is generally employed to produce the TE passage of the nozzle airfoil, casting cannot reliably form the TE passage at the small sizes that may be necessary for proper performance of the nozzle and the nozzle airfoil. That is, casting processes are experimental for small TE passages and have inherent problems with the maintenance of wall thicknesses thereof.